of parallel fault blocks that form long north – south mountain ranges separated by wide , high @ - @ desert valleys . the trout creek mountains are up ##lift ##ed and tilted blocks with steep es ##car ##pment ##s along the southern and eastern sides of the range . the southern area of the range , known as the granite ##s , has numerous out ##cr ##op ##ping ##s of cretaceous age granite . these granite out ##cr ##ops are commonly found in the eroded valleys below the volcanic ridge ##lines . the trout creek mountains are composed mostly of basalt from a shield volcano that once stood where ste ##ens mountain is today . crust ##al thin ##ning and the yellowstone hot ##sp ##ot , which
of parallel fault blocks that form long north – south mountain ranges separated by wide, high @ - @ desert valleys. the trout creek mountains are uplifted and tilted blocks with steep escarpments along the southern and eastern sides of the range. the southern area of the range, known as the granites, has numerous outcroppings of cretaceous age granite. these granite outcrops are commonly found in the eroded valleys below the volcanic ridgelines. the trout creek mountains are composed mostly of basalt from a shield volcano that once stood where steens mountain is today. crustal thinning and the yellowstone hotspot, which